If you are planning to change the meta tags programatically, then I have a simple solution for you.
As you know that in ASP.Net you always have the ability to add the attribute: Runat="server" .
Using this attribute, you can access your controls at runtime, even for the tags that are in the <head></head> portion of your page (which include meta and title tags)
Go to your HTML code page, and modify the title tag to look like:
<title id="pgTitle" runat="server">Some Title Here</title>
Then add the following two meta tags to your code under the title tag:
<meta name="description" content="description" id="metaDescription" runat="server" />
<meta name="keywords" content="keys" id="metaKeywords" runat="server" />
So, we have just set for every tag an ID, and added the runat="server" attribute. This way we can access these controls from the code behind page.
Double click on the page to go to the "OnLoad" event. Place there the following:
pgTitle.InnerText = "New Page Title created on runtime "
metaKeywords.Attributes("content") = "these, are, my keywords, set on, runtime"
metaDescription.Attributes("content") = "This is the text for description meta tag set on runtime"
Now save the page and load it in browser to see the effect.